Well, though I can't find the quote from Matthew Wiener, I'm sure he suggested that each series would jump forward two years. If that's true then I think Season Three, rather than focussing on the JFK assassination itself, is more likely to cover its aftermath as well as the other major issues and events of 1964 America - Beatlemania, Civil Rights and the start of Vietnam. Still, whatever it touches on I've no doubt that Mad Men will continue to be superlative.